1. Field of the Invention
The present invention relates generally to a dough mixer. More specifically, the invention relates to a dough mixer, in which a material feeding inlet and a dough discharging outlet are provided at upper and lower portions of a housing having disposed therein a mixing member.
2. Description of the Related Art
A dough mixer having a dough material feeding inlet and a dough discharging outlet at upper and lower portions of a housing having disposed therein a mixing member is provided with shutter members at the dough material feeding inlet and the dough discharging outlet for closing both during kneading, opening the shutter member at the dough material feeding inlet during feeding of the material and opening the shutter member at the dough discharging outlet during discharging of dough.
Conventionally, the shutter member is formed of a metal plate. The shutter member is supported on the housing by guide rails mounted on the stationary portion of the housing and a plurality of gun-metal pins arranged along the guide rails.
In the conventional dough mixer set forth above, upon closing the shutter member, namely upon shutting off the dough material feeding inlet and the dough discharging outlet, difficulty can be encountered due to presence of dough material within a path of motion of the shutter for opening and closing. Also, the dough material can be clamped between the tip of the shutter member and the peripheral edge of the dough material feeding inlet or the dough discharging outlet to block complete shutting off of the shutter member.
In addition, due to the presence of the dough material within the opening and closing path of the shutter member and due to non-uniform frictional resistance between the shutter member and the guide rails and/or the gun-mental pins, the shutter member can become oblique during opening and closing motion to wear the gun-mental pins. Wearing of the gun-mental pins results in direct frictional contact between the dough mixer main body and the shutter member. Wearing also creates small metal chips or metal particles to be mixed to the dough material, which is quite undesirable for a food material.